Conventional wireless devices, including personal electronic devices (PEDs) execute an autoload operation as part of the chip reset sequence to initialize the memory, device configurations, security keys, and other operations. The devices typically include a chip having a controller and a state machine located therein. The state machine reads data that includes, for example, repair and device information into the controller provided by the autoload operation. The data read into the controller is extracted from memory such as read only memory (ROM) or reprogrammable memory such as a fuse ROM circuit.
During the autoload operation, the controller sequentially reads words located in the ROM. Various chip components, for example read access memory (RAM) circuits will request information from the fuse ROM circuit. For protection, security bits are read by the controller from the ROM each time a request is made for information from the ROM. After obtaining the security information, the user information is read from the fuse ROM via a serial path to the requesting chip component.
When the controller is powered down, reset, or enters a sleep mode, the autoload information is lost in both the controller and in the requesting chip components. This may require upon powering-up reexecution of the autoload operation, which is highly time consuming and current memory intensive. For example, a length of 666 elements (longest length known to be used) at a clock speed of 33 MHz, the autoload operation would take approximately 22 milliseconds.
Accordingly, after a conventional device chip controller is powered-down, reset, or enters into a sleep mode, it becomes subject to lost time as a result of the need to reexecute the autoload program. Avoiding such problems by allowing the controller to remain active is power consuming, especially for wireless or mobile PEDs. Furthermore, it is time intensive to require the controller to request security information from the ROM each time information is requested by chip components. However, to allow the information to be sent to the requesting components without acquiring the security information produces potential security violations.